Method of making score lines



W. E. BURNS METHOD OF MAKING SCORE LINES Filed June 1, 1931 Nov. 27, 1934.

lNVENTOR W/I FRED 550mm ATTORNEY .fi'yi Patented Nov. 27, 1934 UNETED STATES METHOD or MAKING SCORE LINES Wilfred E. Burns, Burlingame, Calif., assignor to M. J. B. Company Application June 1, 1931, Serial No. 541,241

3 Claims.

This invention relates to improvements in tearing strip cans or containers, and it has reference more particularly to a method of and means for forming the scored lines whereby the 6 tearing strip is defined; it being the principal object of the invention to form scored lines that are free of all imperfections that are caused or might be caused by use of defective scoring rolls.

Explanatory to the invention, it will be stated that, it is the common practice to score the can body blanks prior to their being formed into the body, and this is done by passing the blank beneath two sharpened rolls which are pressed thereagainst to cut parallel grooves in the blank,

thereby setting off the tearing strip. This method of scoring is satisfactory only so long as the scoring rolls are free of all imperfections in their cutting edges which might operate to destroy the integrity or continuity of the score lines. It is a fact that a nick in the edge of a cutting roll, even so fine as to be undiscernible to the eye or touch, will cause a blank spot in the line of scoring which will be sufficient to permit or cause the tear, when the strip is being removed, to depart from the scored line and thus cause the strip to break -or run out. Also, brittleness or hard spots in the tin plate will cause the rolls to jump in passing over them and this likewise operates to cause blank spots in the line of scoring which are detrimental to proper removal of the tearing strip in that they cause it to run out or break.

The undesirable running out or breaking of the tearing strip has been offset to a certain extent, by the employment of what is termed herringbone scoring consisting of score lines placed at close intervals within the boundary lines of the strip and directed angularly into the boundary 40 lines in the direction of tearing so that, should a tear break away from the boundary line, it will be caught by one of the angular lines and be directed back into its proper channel.

Another method of scoring has been to pro- 45 vide an outer set and an inner set of parallel score lines, the strip normally being removed along the outer score lines, but should the tear break away from the outer lines it will be carried on by the inner ones.

The present invention differs from the first of these prior methods in that it does not seek to return a tear back to the scoring should it break from it, but on the contrary, it provides a method of scoring whereby all imperfections in the scor- 55ing, by reason of defective rolls or hard spots in the tin plate, will be eliminated and score lines will be formed in a manner and of a character that will allow of no tendency for the tears, formed in removal of the strip, to leave them.

The present invention differs from the above mentioned and previously used method of parallel scoring in that it does not seek to to provide supplemental scoring lines to carry the strip in the event of the tear leaving the main line, but to insure the integrity and continuity of the main lines of scoring.

More specifically stated, the objects of the present invention are attained by the use, in forming the score lines, of scoring rolls arranged in tandem; the second set following the path of the first set so that any imperfection in the lines cut by the first rolls, will be corrected by the second set of rolls.

The invention contemplates also that the first set of scoring rolls might be relatively heavy so as to operate to clear a path for the second set which could be sharper and set slightly deeper.

The invention further contemplates setting the first and second rolls in a manner to provide two cuts very close instead of coincident to each other, thereby to weaken the metal so that the tear will follow without breaking out.

Other objects of the invention reside in the details of construction, combination of parts and manner of forming the scoring lines, as will hereinafter be fully described.

In accomplishing these and other objects, I have provided the improved details of construction, the preferred forms of which are illustrated in the accompanying drawing wherein Fig. 1 is a view of a can body blank, showing the formation of the scoring to set off a tearing strip.

Fig. 2 is a side view illustrating the arrangement of the scoring rolls.

Fig. 3 is a plan view of the same.

Figs. 4 and 5 respectively are enlarged cross sectional views showing the formation of the scoring by the first and second sets of rolls.

Fig. 6 is a view illustrating the formation of score lines by the first and second rolls set just slightly offset one from the other.

Referring more in detail to the drawing- 1 designates what may be the usual tin plate blank from which a can body may be formed, and 2 and 3 designate the parallel lines of scoring setting off a removable tearing strip 4 which, as seen in Fig. 1, terminates at one end in a tongue 5 to which a key may be applied to wind up and remove the strip to open the can after it has been seated.

In carrying out the scoring operation in accordance with the present invention, I provide two sets of scoring rolls, as seen in Figs. 2 and 3. The first set of rolls 66 are carried by a shaft 7 rotatable in bearing blocks 8. The second of rolls 9-9 are carried by a shaftlO rotatable in bearings 11. Thezbearingsfi and:. 11j are, mounted adjustably in a block 12 and set screws 13 adjust them to gauge the depth of the cut to be made in the tin plate as it is passed beneath, them. It will be stated here that any of the usual methods of mounting the scoringrolls and of feeding the tin blanks beneath..them- -.might. be employed, and it is not the intention OfpflPj;

plicant to make any claims to details in this respect.

The gist of this invention resides in the arrange;- ment of the second set of rolls to follow exactly within the; path. cut :byithei first sensor tosxfollow so closely. thereto .asgtoaform; parallel lines ,and. to .break: the .meta11,@.in,:the.; interveningspace so; that they are-in efiectpther. same 511116.... 1

In-Fig.,3, I have shown the second set-of rolls arrangedto.follmvexactlyin the path of. the first;

set-of, rolls.- i When; sos arranged it v.is 1. quitegzob-s vious that any imperfection. of the .cutsr.formed by .the first set,.such as-,might bencausedlby a nick 111 a cutting edge, will; be correctedbyzthefollows ing roll in the second set since it Would .be..very unlikely thatthere might'zbe any nick in theusece.

0nd .roll which *wouldxcoincide with that. in the 'edges define theigroove and break. a path :for the cutting edges of the-second set -of:ro11s. c-'Iheacut ting edges of the second set of -.rolls, as seen at 16 in Fig. -5, are quite. sharp, and .theyaresnarrower and are set somewhat: deeperv than those: of the firstset; so. as to make: a clean cut along the ba'se" of .each groove.formed:by.therolls ofwthe first set. In this arrangement the lfirstrolls bear the brunt. of. the roughing. out of the scoring wh-ioh is finished by .thelsecond set which arerelativelyfree of..strain.

In Fig. 6 I have shown'scoringiormed: by the scored lines 17-18 very close to each other as distinguished from their being coincident. In this arrangement the lines are so close together that the tin plate is so broken or weakened between them that they are, in effect, the same as coincident lines.

The advantages of so scoring the blank is that score l-lneswfree of imperfections, -resu-ltantto defective vcuttingedgesof the. rolls, hard spots or brittleness in the tin plate, are eliminated, and, in removal of the tearing strip, the tears will fol- :glOW-r the lines of scoring without tendency of breaking away Furthermore, the herringbone scoring i-s'not required, as a safeguardto remov- ..,.al.=;0f..the..strip. ;,However, it will be mentioned that. thegh-erringbone scoring might still be used if it is desired. I

While 'it is not absolutely essential that the cut- .ting edges-.01? the first set of rolls be wider and relatively blunt as compared to the second set,

this is ,desirableiasait provides-tor use: of'substane tialsrolls.iforzinitially.breakingl the-.metal, to clear the uwamfomthewsecond setl. and it provides for uses of a semndset-thatrcarrbe:relativelysharptoafonmm a 013811261111 groove. If ;thelrolls:arersetg-in. a :mannen-toprovide the as ,,.-paral1e1lgrocvesnslseendnFig.6, it wouldabe prefe erab-le thatrboth :sets tbesthe tsame :and; designed 1 .to cut to the same depth.

olaimasnew; rthereinlandz desire :to; secure by Lets" ters Patent; is?- 1. :Thezmethodof scoring a can .body .Zblankto. set. 01f .tearing. .strip therein: which comprises 11:;

, ,successivelyLimpressing coincident: grooves in the .5 9

1.body blank-,ieach of-whioh: decreases; itsthickness andthefirstzof which is relativelywide, to break 4 the grain; ofnthe: metalv along: the. boundaries.:.of;.:

thexsecond linen .=width= partly; through-the-.blank,;then impressing a relatirelymarrow groove 'within the'baseof the ;.firstgroovec' ,i comprises :breakingztht: grainsofwthemetal along u .,.a line 50f: substantial widthbyzimpressingaa groove.

partly through the blank,rthenaimpressingaa rela- .-,tively. narrow; groovercentrally: within: .the .base of the ifirstrfiormed groove; 1,.

WIL'FRED E. LBURNSE' two sets of rolls settslightlyt ofiset :so as; to-*iorm Having :sthusrdescribedarmy :invention, .what; I 1

2. :A fmethiodrof scoring metal blanks Whichw 1; comprises impressing. a groove c-t'ofc-tsubstantial 3. A ineehpd zofzascoringwmetalz blanks '..which' 1 1 

